Ponce said the increase is a serious concern because heroin use is linked to violent crime.

"In addition to these drugs being shipped into Hawaii via mail services, they are also being transmitted via the dark web on the internet. People are now using crypto-currency to purchase these dangerous drugs," Ponce said.

Ponce said drug traffickers have turned to street drugs since it became more difficult to obtain large amounts of prescription drugs.

"With this influx of illicit street drugs, KPD has become more aggressive in enforcement efforts," Ponce said. "We continue to focus on quickly identifying dealers and disrupting the flow of these drugs into Kauai."

Kauai's Prosecuting Attorney Justin Kollar said 10 years ago he had one deputy prosecutor handle all the drug cases in addition to other cases. But now, he said they have three deputies handling drug cases full time.

"Those cases almost all involve opioids and/or methamphetamine," Kollar said. "Street drugs are extremely dangerous because they are usually adulterated with other substance like fentanyl or other extremely potent synthetic opioids," Kollar said.

The problem with opioids, he said, is that it does not discriminate.

"Everyone on Kauai knows or is related to someone struggling with addiction, whether or not they know it," Kollar said.

Aaron Hoff, founder of the Keala Foundation, said the island's Adolescent Treatment and Healing Center is scheduled to open in late November.